In January 2019, a scientific expedition aboard the icebreaker Nathaniel B. Palmer prepares to journey to Antarctica to study Thwaites Glacier, also known as the Doomsday Glacier, due to its potential to significantly impact global sea levels. The team, consisting of 26 scientists and 31 crew members (including the author), is part of a joint research project by the National Science Foundation and the British Antarctic Survey. Their mission involves mapping the seabed beneath the glacier, analyzing ocean currents that bring warm water to its base, and examining sediments to understand historical patterns of retreat. The urgency of this research lies in determining whether the West Antarctic ice sheet is on the verge of an unstoppable collapse, which could lead to catastrophic sea-level rise affecting coastal cities worldwide. In the 1970s, glaciologists like John Mercer and Hans Weertman theorized about marine ice-sheet instability. They warned that warm ocean waters could cause glaciers resting below sea level to retreat rapidly, leading to significant sea-level rise—a prediction that is becoming increasingly relevant as signs of instability in glaciers like Thwaites emerge.

The researchers on this expedition use unconventional methods, including tagging Weddell seals to collect data on ocean temperatures and salinity beneath the ice shelves.